687697919 has 4 divisors (see below), whose sum is σ = 687784344. Its totient is φ = 687611496.

The previous prime is 687697897. The next prime is 687697939. The reversal of 687697919 is 919796786.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 687697919 - 2¹² = 687693823 is a prime.

It is a super-2 number, since 2×687697919² = 945856855593861122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687697939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29912 + ... + 47645.

It is an arithmetic number, because the mean of its divisors is an integer number (171946086).

Almost surely, 2^687697919 is an apocalyptic number.

687697919 is a deficient number, since it is larger than the sum of its proper divisors (86425).

687697919 is an equidigital number, since it uses as much as digits as its factorization.

687697919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86424.

The product of its digits is 10287648, while the sum is 62.

The square root of 687697919 is about 26223.9950999080. The cubic root of 687697919 is about 882.6717694040.

The spelling of 687697919 in words is "six hundred eighty-seven million, six hundred ninety-seven thousand, nine hundred nineteen".